The machine wants files like this. If you open the certificate you will see that the numbers match the hash provided within the certificate. This is so that the canonical hash of the certificate matches the name of the file. Remember: A certificate may contain multiple hostnames and aliaes, but it has only one hash.

50a694ac.0
5170a0d9.0

But me? I'm a human and those names are hard to decipher. So I use human-friendly symbolic links like this:

www.example.org.pem -> 50a694ac.0
wiki.example.org.pem -> 5170a0d9.0

I my experience, the names www.example.org.pem and wiki.example.org.pem are usually symbolic links to the files named like 50a694ac.0. In your example you had the opposite-- the human-friendly names existed but not the hashed names. The human-readable names are sometimes optional.